Press for moldings

Abstract

Am improved press for molding ceramic material which has a base frame on which a first carrier is rigidly mounted and which fixedly supports a stationary punch. A stripper platen is slidably movably supported on said first carrier and is adapted to be reciprocated therein by third piston and cylinder means mounted in said first carrier. The stripper platen includes an annular chamber disposed around the stationary punch for receiving granular ceramic material from a hopper mounted in the base frame. A second carrier is also rigidly mounted in the base frame and supports first and second cylinder and piston means. The first cylinder and piston means serves to support a movable punch which exerts the main molding pressure on the ceramic material when the stationary and movable punch are in the molding position. The second cylinder and piston serve to move the movable punch towards and away from the stationary punch and to exert supplemental pressure on the movable punch during the molding process.

We claim: 
     
       1. In an improved press for molding ceramic material having a base frame on which a first front carrier is mounted for fixedly supporting a first stationary punch, and a second rear carrier is mounted for reciprocally movably supporting a second punch coaxially with respect to said first punch, and first and second horizontally slidably movable support frames respectively reciprocally movably mounted via piston-cylinder means on said first and second carriers, and male-female mold means respectively operatively mounted on said first and second punches for pressing a ceramic molding therebetween, the improvement comprising (a) said second support frame on which one half of said male-female mold means is mounted is operatively fixedly connected to a first pair of piston rods having a first pair of pistons, said first pair of pistons being mounted in a pair of cylinders which are fixedly mounted in said second carrier, said pair of cylinders being operatively connected to a source of hydraulic pressure so as to form with said first pair of pistons first double-acting piston-cylinders, and second pistons and piston rods operatively mounted in said pair of cylinders so as to function as flying pistons therein, each of said pair of cylinders having a rear end wall remote from said second carrier which is provided with a bore, said second piston rods extending through said bores and being slidably disposed therein, and limit stop means respectively adjustably operatively mounted on the free ends of said second piston rods to limit the advance of the corresponding half of said male-female mold means;   (b) a second piston-cylinder means is operatively connected to said second support frame and only exerts pressure on the corresponding half of said male-female mold during the molding process, thereby compressing the ceramic molding at a ratio of about 2:1;   (c) stripper means operatively mounted on said first support frame, a pair of rods being slidably mounted in said first front carrier and fixedly secured to said first support frame, a third double-acting piston-cylinder being operatively mounted in said base frame and said pair of rods being connected to said stripper means being slidably in said first front carrier, said third double-acting piston-cylinder also being operatively connected to a source of hydraulic pressure; and   (d) including first and second permanent magnet means respectively operatively connected to said stationary and movable punch, said stationary and movable punch being respectively supported on said first front carrier and said horizontally slidably movable support frame via said first and second permanent magnet means, whereby the space between said first and second punches is laterally substantially freely accessible when said press is in an inoperative position.   
     
     
       2. The improved press for molding ceramic material as set forth in claim 1, wherein said first pair of pistons which form with said pair of double-acting piston cylinders are adapted to exert additional molding pressure on the outer zone of said second punch. 
     
     
       3. The improved press for molding ceramic material as set forth in claim 2, wherein said stripper means includes a platen defining an annular chamber around said stationary punch permitting a lateral flow about said stationary punch of material to be pressed. 
     
     
       4. The improved press for molding ceramic material as set forth in claim 3, wherein said annular chamber has an inlet in its upper region and is closed in its lower region. 
     
     
       5. The improved press for molding ceramic material as set forth in claim 4, including a hopper mounted on said base frame immediately above said stripper means and adapted to receive ceramic material and conduct it to said annular chamber. 
     
     
       6. The improved press for molding ceramic material as set forth in claim 5, wherein the stripper means include stop means adapted to coact with said first horizontally slidably movable support frame to limit the movement of said stripper means and third double-acting piston-cylinder.